Hydrocarbon Sample Loop Conditioning for Wax Fouling Prevention
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing methods for on-line analysis of hydrocarbon streams, such as crude oil, suffer from fouling issues in sample loops, primarily attributed to waxes rather than inorganic compounds, leading to reduced accuracy and potential plugging, which compromises refinery process optimization.
Innovation Solution
Conditioning the hydrocarbon fluid to be passed through the sample loop at temperatures greater than 120 °C and flow rates greater than 20 litres per minute, with a target flow velocity of greater than 0.5 m/s, to prevent wax deposition and fouling, while also considering the use of filters and backwashing to manage solids.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the hydrocarbon sample is passed through the sample loop at normal operating conditions, then the analysis can be performed continuously, but fouling and plugging occur due to wax deposition
Solution Approach 1:
The patent applies parameter changes by heating the hydrocarbon sample to temperatures above the wax appearance point (typically above 100°C) before it enters the analysis device. This temperature parameter change prevents wax crystallization and deposition, allowing continuous analysis without fouling. The heated sample is then cooled back to process temperature after analysis.
Solution Approach 2:
The patent implements preliminary action by pre-heating the hydrocarbon sample in a heat exchanger before it reaches the analysis device. This preliminary heating action removes the harmful wax deposition tendency in advance, ensuring the sample remains in a wax-free state throughout the analysis process.
2Reliability
If filters are used to remove inorganic solids, then protection of the analysis device is improved, but the filters become plugged by wax deposits
Solution Approach 1:
The patent inverts the conventional approach by not relying on filters to prevent wax deposition. Instead, it heats the sample to prevent wax formation in the first place, making filtration unnecessary for wax removal. This inversion of the problem-solving approach eliminates the filter plugging issue while maintaining device protection.
Solution Approach 2:
The patent extracts the wax prevention function from the filtration system and implements it through thermal processing. By removing the wax deposition problem through heating, the system eliminates the need for filters to handle wax, allowing filters to only perform their primary function of removing inorganic solids without becoming plugged.
3Object-affected harmful factors
If the sample loop is heated to prevent wax deposition, then fouling is reduced, but energy consumption increases
Solution Approach 1:
The patent applies partial heating by only heating the sample portion that passes through the analysis device, rather than heating the entire hydrocarbon stream or the complete sample loop. This partial action approach reduces energy consumption while still preventing wax deposition in the critical analysis zone.
Solution Approach 2:
The patent implements continuous heating of the sample throughout its passage through the analysis device, ensuring wax prevention is maintained continuously during the analysis process. This continuous useful action eliminates intermittent fouling issues while optimizing energy use to only when and where needed.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach significantly reduces fouling and plugging in the sample loop, ensuring more accurate and continuous analysis of hydrocarbon streams, thereby optimizing refinery processes like desalting by maintaining the integrity of equipment and improving process efficiency.
Implementation Method 1
heating the sample so that it is passed to the analysis device at a temperature of greater than 120°C
Implementation Method 2
passed around a sample loop... at a flow rate of greater than 20 litres per minute
Data Source
Figure 1
Figure 2
AI summary
A process for analysing a hydrocarbon stream comprises: withdrawing a hydrocarbon sample from a hydrocarbon stream (12); passing the hydrocarbon sample to an analysis device (16) at a target temperature of greater than 120 °C and a target flow rate of greater than 20 litres per minute; and returning the hydrocarbon sample to the hydrocarbon stream (12). The process may be used for the on-line analysis of crude oil, in order to optimise a refinery operation.